All officials spoke on condition of anonymity to discuss matters of intelligence.
The latest incidents bring to a total of four bomb-making sites that the United States has shared with Pakistan only to have the terrorist suspects flee before the Pakistani military arrived much later. The report does not bode well for attempts by both sides to mend relations and rebuild trust after the U.S. raid on May 2 that killed Osama bin Laden in Abbottabad, a Pakistani army town 35 miles from the capital Islamabad.
The Pakistanis say they believe the Americans violated their sovereignty by keeping them in the dark about the raid. U.S. officials say believe that bin Laden's location proves that some elements of the Pakistani army or intelligence service helped hide the al-Qaeda mastermind, bolstering their argument that the raid had to be done solo.
The U.S. officials explained Saturday how they first offered the location of the third, and then the fourth site, to give Pakistan another chance to prove it could be trusted to go after the militants.
In the tradition of "trust but verify," the Americans carefully monitored the area with satellites and unmanned drones, to see what would happen, after sharing the information a third and fourth time, the officials said.
In each case, they watched the militants depart within 24 hours, taking any weapons or bomb-making materials with them, just as militants had done the first two times. Only then did they watch the Pakistani military visit each site, when the terror suspects and their wares were long gone, the officials said.
Pakistan's army on Friday disputed reports that its security forces had tipped off insurgents at bomb-making factories after getting intelligence about the sites from the United States. The army called the assertions of collusion with militants "totally false and malicious."
